CSIP: PRELIMS BOOSTER SERIES-349 Science And Technology


Sickle Cell Anemia


The U.S. Food and Drug Administration (FDA) has granted approval for two gene therapies for sickle cell disease.

Sickle Cell Anemia

Sickle cell anemia (SCA) is a genetic blood disorder characterized by the presence of abnormal hemoglobin (HbS). HbS is a mutated form of hemoglobin that causes red blood cells to become stiff and sticky, resembling the shape of a sickle or a crescent moon. These sickle-shaped red blood cells have a limited lifespan and can easily block blood flow, leading to various complications.


  • SCA is an inherited disorder caused by a mutation in the HBB gene, which is responsible for making the beta chain of hemoglobin. This mutation is passed down from parents to children. A child will only develop SCA if they inherit two copies of the mutated gene, one from each parent.


  • Fatigue
  • Shortness of breath
  • Pale skin
  • Jaundice (yellowing of the skin and eyes)
  • Delayed growth
  • Painful episodes (pain crisis) caused by blocked blood flow
  • Frequent infections


  • Complete blood count (CBC): This test measures the number and different types of blood cells in the body.
  • Hemoglobin electrophoresis: This test identifies the different types of hemoglobin present in the blood.
  • DNA testing: This test can confirm the presence of the genetic mutation that causes SCA.


  • Pain management: Medications such as pain relievers and opioids can help manage pain during pain crisis.
  • Hydroxyurea: This medication can help reduce the frequency and severity of pain crisis.
  • Blood transfusions: Blood transfusions can help increase the number of healthy red blood cells in the body.
  • Bone marrow transplant: This procedure can replace the bone marrow with healthy bone marrow from a donor.
  • Gene therapy: This is an experimental treatment that aims to correct the genetic mutation that causes SCA.

Genetic counseling can help couples with a history of SCA understand their risk of having a child with the disorder. Couples can also consider prenatal testing to determine if their unborn child has the SCA gene.